Anaerobic and aerobic oxidation of ferrous iron at neutral pH by chemoheterotrophic nitrate-reducing bacteria
Anaerobic and aerobic oxidation of ferrous iron at neutral pH by chemoheterotrophic nitrate-reducing bacteria
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DOI：
10.1007/s002030050555
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发表时间：
1998-02-01
影响因子：
2.8
通讯作者：
Schink, B
中科院分区：
文献类型：
--
作者：
Benz, M;Brune, A;Schink, B
在pH 7.2和30 ℃条件下，用来自各种淡水、半咸水和海洋沉积物的沉积物样品接种的10种厌氧富集培养物中有9种在含有硝酸盐和有机共基质的矿物介质中表现出亚铁氧化。厌氧硝酸盐依赖的亚铁氧化是一个生物过程。从咸水沉积物中分离的菌株（菌株HidR2，一个能动的，nonsporeforming，革兰氏阴性杆菌）被选择用于进一步研究在乙酸盐作为共底物的存在下亚铁的氧化。菌株HidR2在pH 7.2和30 ℃下在少量乙酸盐（0.2和1.1 mM之间）存在下有氧和厌氧氧化0.7和4.9 mM之间的亚铁。该菌株从厌氧亚铁氧化中获得生长所需的能量，并且在限制乙酸供应时，氧化的铁与提供的乙酸的比率是恒定的。在pH值约为7的条件下，用硝酸盐厌氧氧化亚铁的能力似乎是嗜中温微生物中广泛存在的能力。由于硝酸盐依赖的铁氧化关闭的铁循环内的缺氧区的沉积物和有氧铁氧化提高了再氧化的亚铁到三价铁在好氧区，这两个过程增加了铁的重要性，作为一个短暂的电子载体在营业额的有机物在天然沉积物。
Nine out of ten anaerobic enrichment cultures inoculated with sediment samples from various freshwater, brackish-water, and marine sediments exhibited ferrous iron oxidation in mineral media with nitrate and an organic cosubstrate at pH 7.2 and 30 degrees C. Anaerobic nitrate-dependent ferrous iron oxidation was a biological process. One strain isolated from brackish-water sediment (strain HidR2, a motile, nonsporeforming, gram-negative rod) was chosen for further investigation of ferrous iron oxidation in the presence of acetate as cosubstrate. Strain HidR2 oxidized between 0.7 and 4.9 mM ferrous iron aerobically and anaerobically at pH 7.2 and 30 degrees C in the presence of small amounts of acetate (between 0.2 and 1.1 mM). The strain gained energy for growth from anaerobic ferrous iron oxidation with nitrate, and the ratio of iron oxidized to acetate provided was constant at limiting acetate supply. The ability to oxidize ferrous iron anaerobically with nitrate at approximately pH 7 appears to be a widespread capacity among mesophilic denitrifying bacteria. Since nitrate-dependent iron oxidation closes the iron cycle within the anoxic zone of sediments and aerobic iron oxidation enhances the reoxidation of ferrous to ferric iron in the oxic zone, both processes increase the importance of iron as a transient electron carrier in the turnover of organic matter in natural sediments.